Fastener for securing an electrical device to an opening



Aug. 11, 1964 A. J. FISCHER 3,144,503

- FASTENER FOR sscuxmc AN ELECTRICAL DEVICE TO AN OPENING Filed Feb.2:5, 1962 A FIG.6

j I 26 34 INVENTOR 38 no ALBERT J. FISCHER as 32 svz jw ATTORNEY UnitedStates Patent 3,144,503 FASTENER FOR SECURING AN ELECTRICAL DEVICE TO ANOPENING Albert J. Fischer, P.0. Box 218, DeLeon Springs Heights, Fla.Filed Feb. 23, 1962, Ser. No. 175,137 7 Claims. (Cl. 174-52) Thisinvention relates to a fastener for securing an electrical device to aterminal box and is particularly well suited for the attachment of smalltransformers of the types used for door bells through the openingsprovided in outlet boxes by the removal of their knockout discs.

The present invention represents certain improvements over a device fora similar purpose disclosed in the patent to Bladh, 2,819,331, datedJanuary 7, 1958. In accordance with the present invention, when theassembly screw is advanced in a tightening direction, any bending of thefastener resulting therefrom tends to improve the connection with theoutlet box both mechanically and electrically.

It is among the objects of the present invention to provide a fastenerfor securing an electrical device to a terminal box having a walldefining an opening comprising a base portion secured to a surface ofthe device, an inclined portion diverging from one end of the baseportion to define a notch with the surface for reception of the wall,afirst leg extending from the other end of the base portion, a secondleg substantially parallel to the first extending from the inclinedportion defining an acute angle with the base portion, the second legcontaining a threaded opening, the first leg containing an openingaligned with the threaded opening and located nearer the base than thethreaded opening, and a screw threadedly mounted in the threaded openingand freely movable through the opening in the first leg for engagementwith the wall. The inclined portion preferably has a reduced edge forengagement with the wall. The fastener is preferably unitary and ispreferably riveted to the surface of the transformer or other device.The maximum distance between the legs is preferably less than adimension of the opening in order to facilitate introduction of thefastener through the opening during assembly. The maximum dimension ofthe notch is preferably greater than the thickness of the wall of theterminal box so that the entire thickness of the wall will lie withinthe notch under assembled conditions.

A more complete understanding of the invention will follow from adescription of the accompanying drawings wherein:

FIG. 1 is a front elevation of a conventional outlet box on which atransformer has been mounted in accordance with the present invention;

FIG. 2 is a sectional elevation taken along line 2-2 of FIG. 1;

FIG. 3 is a fragmentary elevation on an enlarged scale taken along line33 of FIG. 2;

FIG. 4 is a further enlarged elevation of the fastener;

FIG. 5 is a plan view of the fastener of FIG. 4; and

FIG. 6 is a plan view of a blank prior to bending to form the fastener.

A conventional outlet box 10 provided with the usual knockout discs 12is shown in FIG. 1 as having one of its discs removed from its side Wall14 to receive a fastener 16 therethrough for the mounting of atransformer flee 18 or other electrical device in fixed relationshipwith respect to the wall.

The fastener is provided with a base portion 20 whose lower surface 22lies in contact with the transformer housing 18 to which it is securedby means of rivets 24 extending through openings 26 in the base portionand registering openings in the transformer housing. An inclined portion28 diverges from one end of the base portion 20 to define a notch 30whose maximum dimension exceeds the thickness of the wall 14 so thatunder assembled conditions as depicted in FIG. 3, the entire thicknessof the wall 14 lies within the notch 30. The opposite edges of theinclined portion 28 are dimpled or otherwise reduced to provide bitingedges 32 which penetrate the material of the outlet box wall 14 forimproved electrical and mechanical engagement. A leg 34 extends from theopposite end of the base portion and a second leg 36 substantiallyparallel to the leg 34 extends from the inclined portion 28 defining anacute angle with the base portion 24. The second leg 36 contains athreaded opening 38 in alignment with an opening 40 formed through thefirst leg 34. The opening 40 is located substantially nearer the base 20than is the opening 38 so that when an assembly screw 42 is introducedthrough the aligned openings 38 and 40, its thread 44 will engage thoseof the opening 38 and its unthreaded portion 46 will move freely throughthe opening 40 so that as the screw is tightened by the use of ascrewdriver received in its kerf 46, the abutting end 48 of the screwwill bear upon the edge of the wall 14 exposed by the removal of theknockout disc 12 to advance the fastener and transformer 18 towards theleft as viewed in FIG. 3 to produce an ever tightening engagementbetween the wall 14 and the notch 30. In the event that continuedtightening of the screw 42 is effected even after an adequate engagementhas been produced, there will be a tendency to bend the leg 36 and itsadjacent inclined portion 28 in a direction that tends to furthertighten the connection between the wall 14 and the fastener 16. Thiseffect is in sharp contrast to that produced with a construction of thetype disclosed in the patent above referred to.

In order to facilitate introduction of the fastener through an openingprovided by removal of a knockout disc, the maximum distance between thelegs 34 and 36 measured in a horizontal direction as viewed in FIG. 3will be less than the diameter of the opening through the wall 14. Withthe screw 42 in a retracted position, it will be clear that byintroducing the kerfed end of the screw through the opening first, thefastener will then pass freely through the wall 14, whereupon the screw42 will be advanced to a degree sufficient to produce the desiredelectrical and mechanical connections.

As will be noted from FIG. 2, the transformer primary leads 5% projectfrom the housing of the transformer 18 on opposite sides of the fastener16, through the opening formed through the wall 14 of the outlet box forelectrical connection to the power leads, not shown.

Whereas only one specific form of the invention has been described withrespect to the accompanying drawings, variations suggesting themselvesto those skilled in the art are contemplated as falling within the scopeof the appended claims.

I claim:

1. A fastener for securing an electrical device to a terminal box havinga wall defining an opening compris- ,5, ing a base portion secured to asurface of said device, an inclined portion diverging from one end ofsaid base portion to define a notch with said surface for reception ofsaid Wall, a first leg extending from the other end of said baseportion, a second leg substantially parallel to the first extending fromsaid inclined portion defining an acute angle with said base portion,said second leg containing a threaded opening, said first leg containingan opening aligned with said threaded opening and located nearer saidbase than the threaded opening, and a screw threadedly mounted in saidthreaded opening and freely movable through the opening in said firstleg for engagement with said wall.

2. A fastener according to claim 1 wherein said in clined portion has areduced edge for engagement with said wall.

3. A fastener according to claim 1 wherein said fastener is unitary.

4. A fastener according to claim 1 wherein said fastener is riveted tosaid surface.

5. A fastener according to claim 1 wherein said device is a transformer.

6. A fastener according to claim 1 wherein the maximum distance betweensaid legs is less than a dimension of said opening.

7. A fastener according to claim 1 wherein the maximum dimension of saidnotch is greater than the thickness of said wall.

References Cited in the file of this patent UNITED STATES PATENTS2,819,331 Bladh Jan. 7, 1958

1. A FASTENER FOR SECURING AN ELECTRICAL DEVICE TO A TERMINAL BOX HAVINGA WALL DEFINING AN OPENING COMPRISING A BASE PORTION SECURED TO ASURFACE OF SAID DEVICE, AN INCLINED PORTION DIVERGING FROM ONE END OFSAID BASE PORTION TO DEFINE A NOTCH WITH SAID SURFACE FOR RECEPTION OFSAID WALL, A FIRST LEG EXTENDING FROM THE OTHER END OF SAID BASEPORTION, A SECOND LEG SUBSTANTIALLY PARALLEL TO THE FIRST EXTENDING FROMSAID INCLINED PORTION DEFINING AN ACUTE ANGLE WITH SAID BASE PORTION,SAID SECOND LEG CONTAING A THREADED OPENING, SAID FIRST LEG CONTAININGAN OPENING ALIGNED WITH SAID THREADED OPENING AND LOCATED NEARER SAIDBASE THAN THE THREADED OPENING, AND A SCREW THREADEDLY MOUNTED IN SAIDTHREADED OPENING AND FREELY MOVABLE THROUGH THE OPENING IN SAID FIRSTLEG FOR ENGAGEMENT WITH SAID WALL.